Etching abrasives are particles of a hard, granular material that have sharp corners and edges. They are hard enough and sharp enough that they will erode glass and other materials if they are directed at the surface at a high speed. When they hit the surface, they cause small chips to be broken out of the surface. Over a period of time, the abrasive can erode down below the surface and actually carve into the material.

If you still think that a suitable abrasive for sandblasting is actually sand, then you are living in the dark ages! There are so many different abrasives available now for so many different applications that you practically have to be an abrasive engineer to pick one.

Some of the choices you may be faced with if you are etching and carving glass include glass beads, beach sand (brown), white crystal silica sand, garnet, aluminum oxide (white, brown or pink) and silicon carbide (black or green).These materials will vary in price from less than $4 per hundred pounds to over $200 per hundred pounds. When you consider that in a given blasting job you may be using as much as 50 to 100 pounds or more in an hour, it becomes obvious that you need a little more information before making your purchasing decision.The best abrasives to use are the ones that are the hardest and that have the sharpest, longest lasting corners and edges on the particles. However, those are also the most expensive. In order to make them worthwhile to use, you have to be able to recapture and reuse them over and over. (Which is what most blast cabinets allow you to do.) In recycling the more expensive abrasives, you increase their cost efficiency to the point where they actually cost less to use on a per hour basis than sand or the other cheap materials.The following chart and the additional information included in this page will help make your decision. This chart only shows the uses for the two most popular abrasives, since most people don't use sand or garnet on glass. (Don't even think about using glass beads!) However the cost effectiveness chart at the bottom does show why it is not the cost per pound that is important, it is the cost per hour of use.

Very hard, tough abrasive that cuts glass quickly. Major drawback: generates static electricity which causes dust to cling to the the back of glass being blasted. Makes it hard to see what you are doing if you prefer lighting the glass from the back. Brown is most common & cheapest. White & pink are available - higher purity & cost but no increase in speed. No free silica.

Harder than aluminum oxide, cuts glass faster because it constantly breaks off small pieces, exposing new cutting edges. No static electricity. No free silica. Creates "flashlight effect" of small sparks where particles hit glass, making it easy to see area being blasted. Black is most common; green is sometimes available and is slightly harder but costs much more.

Your decision of which abrasive to use will depend on the cost effectiveness of each abrasive for the job, and your blasting equipment and technique.

The cost effectiveness of an abrasive is a measure of how much glass you can etch per dollar spent on abrasive and labor. The more efficient (faster) an abrasive is, the lower the labor cost to produce an etching. The more times you can recycle an abrasive without losing etching speed, the lower the abrasive cost (If the abrasive loses etching speed with continued reuse, the labor cost necessarily goes up).The equipment you are using is important because that determines whether or not you can recycle the abrasive. If you have a good blast cabinet or blast room in which to etch, you can use any of the abrasives which can be recycled.

If you are using a leaky, poorly constructed cabinet or blast room, or if you are blasting outside, you will lose a lot of abrasive. You can't use the recyclable abrasives in those situations since they are a lot more expensive per pound than the others.

Cost Effectiveness of Abrasives

Type of abrasive

Etching speed

Number of cycles

Cost per 100 pounds

Cost of abrasive used in 50 cycles (100 lb quantity)

Approx. cost per hour of use

Brown sand

Medium slow

2

$5.00

$125.00

$1.25

White crystal silica sand

Medium slow

2

$5.00

$125.00

$1.25

Garnet

Medium

4-8

$25.00

$150.00

$1.50

Aluminum Oxide

Medium fast

60-80

$100.00

$63.00

$ .63

Silicon Carbide

Fast

80-100

$150.00

$75.00

$ .75

1) Cost figures are approximate and may vary with different suppliers. Figures for number of cycles vary with type of blasting done and the technique of person doing the blasting.

2) The number of cycles for all materials except carbide depends how quickly the particles get dull (i.e. how hard the material is). Carbide never gets dull, it just breaks down into finer and finer particles (see "Other Facts" in table #1). As the particles get smaller, more are sucked out of the cabinet by the dust collector. With a stronger vacuum system, you get fewer cycles per pound of grit (although there is less dust to obscure vision).

3) Based on estimated average of 2 hours per cycle, 100 pound quantity.

True GritSize does matter! The size of grit you use has a lot to do with the way your finished etchings will look. The size of the grit is specified by number, with the higher numbers denoting smaller particle sizes. A smaller grit size cuts slightly slower, but leaves a smoother finish on the glass. Another consideration is that the larger grit sizes cut faster, but not significantly faster if you are using an abrasive like silicon carbide.

The most common grit sizes for etching windows and architectural size pieces are 120 to 150. For a finer finish on trophies and glassware, 180 to 220 is used. Micro blasting equipment uses 220 to 400 grit. When exclusively blasting wood or stone, the most common grits are 30 to 80.

Conclusions
As you can see from the table above, the abrasives which cost less per pound to purchase, actually cost much more per hour to use since they cannot be effectively recycled.

The really significant advantage to carbide or oxide is the fact that they etch glass about twice as fast as the other abrasives. So, in addition to savings on materials costs, the oxide and carbide provide an almost 50% saving in labor costs as well.

There is so little difference in cost per hour between carbide and oxide, your choice between the two will depend more on whether you are willing to put up with the static electricity of the oxide and how much benefit you feel the flashlight effect of the carbide provides. Both of these considerations point to using carbide, which is what we heartily recommend. As far as safety goes, the Material Safety Data Sheets information on both materials classifies them only as "nuisance dusts", and not as hazardous materials.

It is obvious from these facts that if you have blasting equipment which captures the grit and allows you to recycle it, you should be using either the carbide or the oxide. If you don't have such equipment, you should seriously consider getting it, because your savings in labor and abrasive could pay for the equipment in a very short time.

Please note: We only list the most commonly ordered abrasives here on the site. If you have a requirement for an abrasive not listed here, please contact us. We can order almost any silicon carbide or aluminum oxide abrasive and have it shipped direct to your door.